It is narrated from Hasan al-Basri, may Allah have mercy on him, that he said: Are you not amazed at Ibn Malik ibn Mundhir, that he went out seeking elderly new Muslim farmers from among the Romans, examined them, and ordered that they be circumcised, even though it was cold (and the wound is also painful)? I learned that some of them even died. When Romans and Abyssinians accepted Islam with the Messenger of Allah, peace and blessings be upon him, nothing was checked regarding them (whether they had been circumcised or not).
Hadith Referenceالادب المفرد / كتاب الختان / 1251
Hadith Gradingالألبانی:صحيح الإسناد موقوفًا و مرسلًا و رواه الخلال من طريق أحمد بسنده الصحيح عن الحسن
Hadith Takhrij«صحيح الإسناد موقوفًا و مرسلًا و رواه الخلال من طريق أحمد بسنده الصحيح عن الحسن : 197/150»
Explanation & Benefits
Shaykh Maulana Usman Muneeb
Benefits and Issues: If Hasan al-Basri rahimahullah intended by his statement that whether someone is circumcised or not should not be given importance, then this position of his is not correct, because the Messenger of Allah sallallahu alayhi wa sallam commanded new Muslims to undergo circumcision (khitan) and to cut their hair. Undoubtedly, the Messenger of Allah sallallahu alayhi wa sallam did not search out and investigate people, but if the ruler of the time deems that people are being negligent in this matter, then he may investigate.
Source: Fadlullah al-Ahad: Urdu Commentary on al-Adab al-Mufrad, Page: 1251